Side feed reverberatory furnace



July 25, 1967 R. T. M KIE SIDE FEED REVERBERATORY FURNACE 3 Sheets-Sheet 1 INVENTOR ROBERT T. Mc Kl E ATTORNEYS Filed Dec 28, 1965 July 25, 1967 T. M KIE SIDE FEED REVERBERATORY FURNACE 5 Sheets-Sheet 2 Filed Dec. 28, 1965 N wE INVENTOR ROBERT T. McKlE find/u hnmab, 777M4 4 we'l d Gala "LL ATTORNEYS July 25, 1967 R. T. M KIE SIDE FEED REVERBERATORY FURNACE 5 Sheets-Sheet 3 Filed Dec. 28, 1965 INVENTOR. ROBERT T. Mc KIE ATTORNEYS United States Patent 3,332,673 SIDE FEED REVERBERATORY FURNACE Robert T. McKie, Marenisco, Mich., assignor to Copper Range Company, New York, N.Y., a corporation of Michigan Filed Dec. 28, 1965, Ser. No. 517,034 6 Claims. (Cl. 263-40) This invention relates to side-feed reverberatory furnaces for the treatment of copper concentrates and the like to produce copper matte, and has for its object the provision of apparatus for controlling the feed of the concentrate.

The invention is concerned with side-feed reverberatory furnaces having feed slots extending substantially the full length of the two opposite long sides of the furnaces, a feed conveyor system which carries feed concentrate to and deposits it in the feed slots, and provides a conveyor system including a bottomless feed duct mounted over each feed slot which is under superatmospheric air pressure, and means responsive to changes in the air pressure to operate the conveyor system.

In the normal operation of the side-feed reverberatory furnace of the invention the concentrate feeds uniformly and the concentrate extends almost to the top which acts as an air plug permitting the space at the top of the feed duct to be under air pressure. However, on occasion the banked concentrate in the furnace slides and empties the feed duct which causes a drop in the air pressure. The escaping air protects the conveyor components from heat and flame.

The improved feed conveyor feed system of the invention comprises a feed duct for each side of the reverberatory furnace connected at their ends to enclosed tunnels forming a continuous pressurized circuit in which an endless conveyor operates. In a preferred feed system a Redler type conveyor is used having conveyor arms operating in the top portion of the feed duct and the tunnels of the continuous circuit, and a pull chain operating in a side compartment contiguous with .the circuit which is connected to an air pressure system. Since there is a constant seepage of air through the concentrate this permits a continuous supply of air which keeps the chain cool.

A particularly important feature of the invention is the provision of means responsive to changes in the air pressure of the duct circuit to operate the feed conveyor. In an advantageous embodiment of the invention a pressure responsive device is installed in the feed duct on each side and is so connected electrically to the motor driving the conveyor that it can operate the conveyor in either direction so that in the event of a slide and drop in pressure on one side, the conveyor will move in the direction to carry concentrate the shortest distance from the supply of concentrate, preferably a hopper.

The invention is primarily applicable to reverberatory' furnaces having flat suspended roofs with the feed slots extending along the side edges of the roof. The bottomless feed ducts are upright, preferably rectangular in crosssection having a closed t-op extending several feet above the feed slots and are connected to closed tunnels at the ends of the furnace forming an enclosed circuit for the endless conveyor. Preferably one of the end tunnels is connected to a feed hopper maintained filled with concentrate which feeds through the tunnel which the conveyor drags through and pulls the concentrate through the circuit. It is preferred to provide two separate air systems, one for each side for supplying air to the pull chain compartment and the feed duct on each side and a pressure responsive means on each side connected to the conveyor drive motor. In a preferred embodiment of the invention the motor is reversible and can be operated by a timer or the like, to move the conveyor in either direction.

The conveyor motor is preferably operated by an onoff timer which is set to operate, for example, one minute out of four or five depending on the production required. If a slide occurs and the air pressure drops on one side, the pressure responsive control will start the conveyor to supply concentrate in the shortest distance from the feed hopper.

The invention greatly reduces the labor required in probing to dislodge material which hangs up in the usual relatively small feed chutes of present reverberatory furnaces. The invention also greatly reduces the concentrate dust containing sulfides which circulates about the top of the furnaces and is lost or settles on the roofs causing a deleterious chemical reaction with the refractory brick hangers. This accumulation also externally insulates and thus causes overheating of the roof refractory.

In the accompanying drawings:

FIG. 1 is a plan view with parts in section of a reverberatory furnace illustrating apparatus of the invention;

FIG. 2 is a sectional View at 2-2 of FIG. 1;

FIG. 3 is a sectional view at 33 of FIG. 1; and

FIG. 4 is an enlarged sectional view at 44 of FIG. 1.

The reverberatory furnace illustrated in the drawings is a'type used to form copper matte from copper sulfide concentrates, or sulfide ore. The furnace includes a thick refractory bottom 1, refractory brick side walls 2 and 3, and refractory brick end walls 4 and 5. The exterior of the furnace may have a steel shell 6 but such a shell is usually not used. The sides and end walls are formed of refractory brick which is held in position by several upberatory furnace illustrating apparatus of the invention; right I beams which are bridged over the top by several horizontal tie beams B. The roof 7 is generally flat and formed of refractory bricks which are supported by wellknown means (not shown). As best shown in FIG. 2 the roof extends to the side walls at the ends but leaves open feed slots 8 and 9 along a substantial length of each side wall.

The furnace end 4 is provided with fuel burners S the flames from which travel the full length of the furnace and pass out the end 5 into a Waste heat boiler (not shown) and then pass into a stack as is the usual practice. The melting of the side banks of concentrate C and its conversion to matte 12 and the separation of slag 13 are too well known to require discussion. The slag and matte are separately tapped from the furnace through tap holes 14 and 15. Directly over each feed slot is mounted a bottomless feed duct 16 and 17 formed of steel plate, and having a closed top 18 and 19. To protect the plate from the hot roof fluid cooled barriers 20 and 21 are mounted between the roof bricks and the inner walls of the feed' duct. The upper inner walls of the feed ducts open into separate compartments 22 and 23 which extend the length of the feed ducts. A preferred conveyor for use in the invention is of the Redler type consisting of a pull chain 24 mounted in and traveling in the compartments 22 and 23, and extending arms 25 which are pulled through the upper parts of the feed ducts.

The feed ducts are connected across their ends by completely enclosed gas tight tunnels 30 and 31 through which the endless conveyor chain 24 and arms 25 travel in a cycle. In order for the conveyor to pass from the feed ducts through the tunnels there is constructed at each connecting corner a gas tight housing G at one end of Which anti-friction bearing rollers R are mounted over which the pull chain is guided. At the other end of the furnace 5 and in the housings G, motor driven rollers M are provided which drive the pull chain. The Redler conveyor system also includes a suitable idler corner and chain drive construction.

As best shown in FIGS. 2, 3 and 4, the sulfide, concentrate C extends from the furnace bottom up into the top portion of the feed ducts 16 and 17 and is also dragged through the tunnels 30 and 31. At any convenient place, for example, at' end a feed hopper 35 is mounted and is supplied with concentrate by a conveyor 36 which dumps the concentrate into the open top of the hopper. When the feed falls below the low-level switch 37 the motor driven conveyor 36 is started and when the feed reaches the high-level switch 38 the conveyor 36 is stopped.

The feed ducts 16 and 17 are provided with an air pressure system 40 and 41, respectively, preferably including connecting with pipes 42 and 43 supplied with air under pressure by motor driven fans 44 and 45 respectively. The pipes 40 and 41 are preferably connected by spaced branch pipes P leading directly into the air compartments 22 and 23. The air compartments and the upper open parts of the feed ducts are maintained under a superatmospheric pressure which keeps the pull chains cool, protects the conveyor components from heat and flame when a slide occurs, and also provides a means for controlling the conveyor movement to maintain the feed ducts full as shown in the drawings.

The on-oif timer 46 is electrically connected to the motors M and can be set to operate the conveyor in suitably selected on-oii cycles, say, one minute out of four or five depending on the production rate. In the upper open parts of feed ducts 8 and 9 pressure sensing devices 47 and 48 respectively are mounted and electrically connected to a reverse drive starter 49 which is connected to the timer 46.

In the operation of the apparatus of the invention, the concentrate C in .the hopper 36 is maintained at the desired level and the conveyor arms 25 which pass through the lower portion of the hopper drag the concentrate through the tunnel 31 and into either feed duct 16 or 17, depending on the direction of travel, and it falls through slots 8 and 9 and accumulates as banks on the furnace bottom. Should no slide occur in the banks of feed in the furnace, which can empty a feed duct, the conveyor will always travel in the same direction on the time cycle selected. However, if a slide takes place, say, in feed duct 16, the sensing device 47 responding to a drop in pressure energizes the reverse drive starter 49 and sets the timer 46 to operate the reverse direction motors M to drive the conveyor in the direction to supply the feed directly from the hopper and this action is continued until the slide opening has been filled and normal operation resumed.

I claim:

1. The improvement in side-feed reverberatory furnaces which comprises a feed slot extending substantially the entire length of each of the two opposite long sides of the furnace, a bottomless feed duct having closed sides and top over each feed slot, an enclosed tunnel at each end of the furnace connected to the two feed ducts forming a closed circuit, a feed hopper for concentrates opening into the circuit, an endless conveyor provided with means to travel in both directions in the feed duct which can drag feed from the hopper to keep the feed ducts 4 V filled and from which the feed falls through the feed slot and forms banks along the sides in the furnace, means for supplying air under superatmospheric pressure to the upper part of the feed ducts, means for operating the conveyor on an on-oit cycle, means responsive to a decrease in air pressure in either feed duct as caused by a slide of concentrate to set the conveyor in motion and fill the space caused by the slide.

2. The improvement in reverberatory furnaces defined in claim 1 which comprises a separate air system supplying air to the feed duct for each side, a separate pressure responsive sensing device for each air system, means associated with the controls for driving the conveyor in either of two directions depending upon which side has a slide.

3. The improvement in reverberatory furnaces defined in claim 1 in which the upper portion of each feed duct has an adjoining compartment in which a pull chain for the conveyor operates, said means for supplying air being connected to said compartment whereby said chain is kept cool and out of contact with the feed concentrate.

4. The improvement in side-feed reverberatories which comprise two opposite long longitudinal sides having feed slots in the roof extending along the major part of each side, a bottomless feed duct over each feed slot extending appreciably above each feed slot and having closed sides and top, closed tunnels connecting the ends of the feed ducts forming a circuit, a feed hopper connected to the circuit, an endless conveyor operable in the circuit for carrying feed from the hopper to the feed slots, whereby the feed accumulates along the sides of the furnace and extends up in the feed ducts to the conveyor leaving a space above, an air system for maintaining a superatmospheric pressure in the space, means for operating the conveyor on an on-olf cycle, and pressure responsive means in association with the space of each feed duct for starting the conveyor should a slide occur which causes a decrease in pressure whereby it fills the space caused by the slide.

5. The improvement in reverberatory furnaces as defined in claim 4 which comprises means for reversing the direction of travel of the conveyor, and means connecting each pressure responsive means to the means for reversing the direction of conveyor travel whereby the conveyor is moved in the direction to supply feed from the hopper directly to the place Where the slide occurred.

6. The improvement in reverberatory furnaces as defined in claim 4 in which the superatmospheric pressure in the circuit escapes through any slide area which is opened by a slide thereby protecting the conveyor from flame and heat. 5

References Cited UNITED STATES PATENTS 1,999,761 4/1935 Howard 263-40 X 2,327,887 8/1943 Halbach et al. 263-40 2,592,010 4/1952 Cole et al. 263-40 FREDERICK L. MATTESON, 13,, Primary Examiner.

J. J. CAMEY, Examiner, 

1. THE IMPROVEMENT IN SIDE-FEED REVERBERATORY FURNACES WHICH COMPRISES A FEED SLOT EXTENDING SUBSTANTIALLY THE ENTIRE LENGTH OF EACH OF THE TWO OPPOSITE LONG SIDES OF THE FURNACE, A BOTTOMLESS FEED DUCT HAVING CLOSED SIDES AND TOP OVER EACH FEED SLOT, AN ENCLOSED TUNNEL AT EACH END OF THE FURNACE CONNECTED TO THE TWO FEED DUCTS FORMING A CLOSED CIRCUIT, A FEED HOPPER FOR CONCENTRATES OPENING INTO THE CIRCUIT, AN ENDLESS CONVEYOR PROVIDED WITH MEANS TO TRAVEL IN BOTH DIRECTIONS IN THE FEED DUCT WHICH CAN DRAG FEED FROM THE HOPPER TO KEEP THE FEED DUCTS FILLED AND FROM WHICH THE FEED FALLS THROUGH THE FEED SLOTS AND FORMS BANKS ALONG THE SIDES IN THE FURNACE, MEANS FOR SUPPLYING AIR UNDER SUPERATMOSPHERIC PRESSURE TO THE UPPER PART OF THE FEED DUCTS, MEANS FOR OPERATING THE CONVEYOR ON AN ON-OFF CYCLE, MEANS RESPONSIVE TO A DECREASE IN AIR PRESSURE IN EITHER FEED DUCT AS CAUSED BY A SLIDE OF CONCENTRATE TO SET THE CONVEYOR IN MOTION AND FILL THE SPACE CAUSED BY THE SLIDE. 